The difference, as I see it, is that the value in the "social/web2.0" site comes mostly from the community (almost entirely in cases like reddit), rather than the application having much inherent value itself, as word processors and spreadsheets (or phone lines) clearly do.
I guess people get enough value out of it to not worry too much, but there is something to the original quote.
Phone lines are as neutral as reddit. They just cost a lot more to install. So if that's the critical difference, then the above remark about web 2.0 reduces to: it's cheaper now to start a startup.
"A naso", I would say that the underlying economics do differ somehow.
They're obviously different for 'end user' applications, even though network externalities touch on those through file formats.
For phone lines, the network effects are obvious: the value is in 1) connections to people you want to contact frequently, and 2) the potential to contact a wide range of people. No money is made from the actual content, though.
With the "social sites", though, they're aggregating massive amounts of user produced content (most of it pretty insignificant on its own), and making money from that.
I am not sure if I prefer a culture where people are expected to give away things for free all the time.
There is no such thing as a free lunch. Even if people give away things for free, they usually expect something in return. Even if it is not money, it could be higher social status, a better place in heaven, or whatever. I don't think it is a problem.
Usually on the web people prefer to give away their PRIVACY for free services. That privacy is in turn converted into advertising.
(This will all change very soon, when people are ready to start paying for a higher - and much more private and secure - level of premium service. You know, the Web will evolve to resemble the "regular' economy more and more, I believe..)
I understood the comment before me differently: I thought it was criticized that the content providers (people putting videos on YouTube) would expect something in return, not that YouTube & Co would expect a payment of sorts. I know that Social Webpages are not really free.
What if your users ask you for money, cos you and your cofounder were bought by google for 1.5billion dollars? Say (big) group of you tube users create an alliance asking founders for money fraction cos "We have created your content you sold!" :) Seems it crazy in social world where people, not you creating your content, generating your visits and advertising income? Seems it crazy in the USA?
(Usability will also 'come into its own,' and find itself as an art and science, I believe.)